Both Zuckerberg and Buffett own large parts of their respective companies, and the vast majority of their wealth comes from their ownership stakes, not their salaries as CEOs. Zuckerberg, in particular, elected to take a symbolic $1 salary in 2013, down from $503,205 in 2012.

Buffett for many years has had one of the lowest base salaries of the S&P 500 CEOs, at $100,000.